1. Field of the Invention
The present invention relates to electronics assembly technology. More particularly, the present invention relates to printed circuit board technology and to an integrated printed circuit board layout scheme for power distribution, power supply decoupling, and signal termination.
2. The Prior Art
Printed circuit boards are well known and widely used in the electronics industry. They allow rapid, repeatable and reliable automated assembly of electronic components into electronic circuits. As circuit technology, especially integrated-circuit technology, has developed, printed circuit technology has necessarily co-evolved to keep pace with the ever increasing complex interconnectivity requirements of electronic circuits and devices which must be mounted on printed circuit boards. Accordingly, double-sided printed circuit boards, plated-through component mounting holes, and multilayer printed circuit board technology has evolved to meet the needs of circuit designers to provide compact and densely functional circuits for electronic systems.
Printed circuit technology has also played a role in circuit development and prototyping. Printed circuit boards have been designed to facilitate breadboarding for prototype circuit development. Such printed circuit boards usually provide a matrix or other network of component-mounting holes connected to conductive traces which provide power distribution to the components. An example of such printed circuit board technology is the provision of power and ground plane conductors on a printed circuit board designed for use with integrated circuit packages. In one configuration, a printed circuit board includes conductive traces connecting the power and ground planes to particular pads associated with holes for mounting of wire wrap integrated circuit sockets. The connectivity pattern between the pads and the power planes is chosen to match the power supply pins commonly employed in selected families of integrated circuit devices.
In another known configuration, power and ground plane conductors are provided on the printed circuit board between and adjacent to rows of component mounting holes. Connections between the plane conductors and the power supply pins on the mounted components are made by placing small bridging clips over selected ones of the component pins and soldering the clips to the pins and to the power plane conductor to form a bridging connection between the pin and the power or ground plane trace on the circuit board. An example of such technology is a printed circuit board, part no. 3682-2, available from Vector Corporation of Sylmar, Calif.
There also are a number of power supply decoupling schemes in use for printed circuit board applications. For example, printed circuit boards have been provided with pairs of contact pads and mounting holes for decoupling capacitors distributed over the surface of the printed circuit board. One of the contact pads of each pair is electrically connected to one of the power plane conductors and the other is connected to the other power plane conductor. An example of a printed circuit board including such a feature is part No. 8096-048, available from Twin Industries, Inc. of Santa Clara, Calif.
In addition, general component connection capability has been available in one form or another in printed circuit board technology. Usually, components are mounted in holes associated with contact pads to which they may be soldered. The components may then be connected to the circuits by techniques such as wire wrapping.
What is lacking in the printed circuit board technology is an integrated solution to the problems of power distribution, power supply decoupling, and signal termination. An ideal solution to this problem would be the provision of a printed circuit board layout which allows the functions of power distribution, power supply decoupling, and signal termination to be available to any component mounting hole and its associated electrical contact pad without resort to additional board space to accommodate the added functionality or the need to employ additional interconnection methods once the component to serve this function has been mounted.